Correspondence Address:James A. OsaikhuwuomwanDepartments of Obstetrics and Gynaecology, University of Benin, Benin City, Edo State Nigeria

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/1116-5898.134532

Abstract

Aim: The aim of the following study is to document the outcome of cervical cerclage in pregnancy. Materials andMethods: A retrospective analysis was undertaken of patients who had cervical cerclage for cervical incompetence at the Obstetrics and Gynecology Department of the University of Benin Teaching Hospital, Benin-City, Nigeria from January 2007 to December 2012. The cerclage was termed successful if the pregnancy was carried to term. Multiple demographic and clinical characteristics and their relationship to cerclage outcome were analyzed. Results: The records of 123 patients who underwent cerclage over the 6 years period reviewed were analyzed. The mean age was 33.3 ± 3.9 and majority (68.3%) were multiparous, with most of them (90.2%) having had a previous miscarriage. Majority (90.2%) had elective cerclage and 4 (3.3%) had emergency cerclage. Overall majority of patients delivered at 37 and 38 weeks gestation 23.6% and 19.5% respectively. Outcome of cerclage was adjudged successful in 92 (74.8%) of cases and failed in 31 (25.2%) cases. The most frequent complication was pre-viable or preterm rupture of membranes (14.6%). Cerclage outcome was not influenced by age, parity, gestational age at cerclage or experience of the surgeon. The mean duration for which pregnancy was prolonged after an emergency cerclage was 2.6 ± 2.4 weeks and emergency procedure was significantly associated with a failed cerclage. Of the 111 patients with previous miscarriages who had cerclage procedure, 68 (61.3%) had term deliveries and 23 (20.7%) preterm births. Fetal salvage rate of 98 (79.7%) was observed. Conclusion: Use of cerclage for suspected cases of cervical incompetence can have an important beneficial effect in carefully selected cases of cervical incompetence even amongst pregnant black African women.

Cervical incompetence describes the failure of the cervix to retain an intrauterine pregnancy to term. It occurs in approximately 1% of all pregnant women, but rises to 8% in those who suffered a second or third trimester pregnancy loss. [1] Cervical incompetence is an important cause of preterm deliveries, however, the exact etiology of pre-term birth in most cases is unknown. Pre-term birth accounts for over 70% of all perinatal mortality and is an important determinant of neonatal and infant morbidity, including neurodevelopmental handicaps, chronic respiratory problems, infections, neonatal intensive care unit admissions and ophthalmic problems. [2] It has been recognized that the prevention of preterm birth is crucial to improving pregnancy outcome. [3],[4] Cervical cerclage has been used widely in the management of pregnancies considered to be at high risk of pre-term delivery from cervical incompetence. Its (cervical cerclage) role is to provide mechanical strength and act as a barrier to prevent infection. [5] However, its potential benefits have been queried as it is an invasive procedure with associated complications. [6]

The efficacy of cervical cerclage, as well as its need have been contentious, some authors terming it an unnecessary intervention while others reported clear beneficial effects. [7],[8],[9],[10] A recent study in London reported that poor outcome after cervical cerclage were more common amongst blacks. [11] This study is therefore aimed at documenting the outcome of cervical cerclage amongst black women in a referral teaching hospital in sub Saharan Africa.

MATERIALS AND Methods

This was a descriptive study conducted at the University of Benin Teaching Hospital on patients who had cervical cerclage performed because of suspected cervical incompetence over a 6 years period (2007-2012) to assess the outcome of pregnancy viz. prolongation of pregnancy and fetal outcome as well as complications resulting from the cerclage. All women who underwent cervical cerclage during the period reviewed were included in the study. The study was approved by the Hospital Ethical Review Committee.

Patients' details were obtained from the case files using predesigned questionnaires. These included; the age of the woman and the gestation period in weeks at the insertion of the stitch. The cerclage was grouped as prophylactic (elective) if it was based on past history, urgent (empirical) in patients without symptoms and diagnosis based on ultrasound suspicion alone and emergency in patients with symptoms; indicated due to prolapsed membranes or cervical dilatation on examination. [12] The cervical dilatation as assessed by the surgeon on digital pelvic examination at operation was obtained from the surgical notes. Record of Immediate and late complications after cerclage were also extracted. The pregnancy outcome was categorized as abortion (below 24 weeks gestation), premature delivery (if before 37 weeks), term delivery (37 weeks up to 42 weeks gestation) and intrauterine fetal demise if any records of fetal death in utero were available. The cerclage was termed successful if the pregnancy was carried to term. The type of labor whether induced or spontaneous and the labor duration was noted. Furthermore the mode of delivery was recorded as either normal vaginal or caesarean section. Data was managed using Spss version 20.0 (Armonk,NY:IBM Corp) and analysis performed using simple descriptive statistics like means, frequencies and cross-tabulations. Multiple demographic and clinical characteristics and their relationship to cerclage outcome were compared using the Student's t-test to analyze the difference between groups in continuous variables while categorical data were analyzed with Chi-square test. All tests were two-tailed and P < 0.05 was considered to be statistically significant.

Results

There were 137 patients who had cerclage inserted (all following a diagnosis of cervical incompetence) during the 6 years period under review; with a total delivery of 17,518 during the study period, the incidence of cervical incompetence was 0.78%. However, out of 137 patients who had the operation, adequate records were available for 123 patients and this therefore comprised the study population.

The demographic and clinical characteristics of the study population are shown in [Table 1]; the mean age was 33.3 ± 3.9. Overall there were more multiparas' (para 1-4) 68.3%; however subanalysis of each parity distribution, showed that the majority were nulliparous, 35 (28.5%), while 31 (25.2%) were para 1, 28 (22.8%) para 2, 18 (14.6%) para 3, 7 (5.7%) para 4 and 4 (3.2%) para 5 and above. There were no cases of cerclage insertion in primigravidae (para0 +0 ). Most of the study population (90.2%) had a previous miscarriage with about 60% of them having 2-3 previous spontaneous miscarriages. Furthermore about 65% of the study population had previous induced abortion. Fifty-nine patients (48%) had previous cerclage in their last pregnancy of which 89.8% were successful. The mean gestational age at cerclage insertion was 14 weeks. Majority (90.2%) had elective cerclage with only a few patients, 4 (3.3%) having emergency cerclage. All cerclage procedure was carried out using regional anesthesia (subarachnoid block), the surgeon was a senior registrar in most cases (69.1%) and a merselene tape was used for majority (82.1%) of the procedure. The mcdonald technique was used for all cases. The mean cervical dilatation at cerclage insertion was about 1 cm; patients remained in the hospital between 1 and 7 days with a mean of 3.7 days. All patients had salbutamol for an average of 2.13 weeks after the procedure; also all patients had prophylactic antibiotics.

Overall majority of patients delivered at 37 and 38 weeks gestation 23.6% and 19.5% respectively, the mean gestational age at delivery was 34.25 ± 6.8 weeks. While 20 (16.3%) had a spontaneous abortion, 25 (20.3%) had preterm deliveries and 78 (63.4%) had term deliveries. Outcome of cerclage was adjudged successful in 92 (74.8%) of cases (this inclusive of 14 preterm deliveries at between 34-36 weeks gestation for obstetric indications such as pregnancy induced hypertension [PIH] and fetal compromise), whereas of the 31 (25.2%) cases of failed cerclage 13 (10.6%) had inevitable abortion (presenting with vaginal bleeding) and 18 (14.6%) had pre-viable or preterm premature rupture of membranes (PROM).

Majority had spontaneous labor onset (48.8%) with a mean duration of 9.42 days to onset of labor from time of cerclage removal. Fourteen (11.4%) had induction of labor either for PIH or intrauterine growth restriction. Eighteen patients (14.6%) and 10 (8.1%) had an emergency and elective caesarean section (CS) respectively for various obstetric indication. Only a minority, 7 (5.7%) of the babies delivered had birth asphyxia with 5 (4.1%) eventual early neonatal death. The mean birth weight was 2.9 ± 0.49 kg; shown in [Table 2].

In [Table 3] and [Table 4]; the relationship between cerclage outcome (viz.: Failed or successful) and patient characteristics was analyzed; the age, parity, gestational age at cerclage placement, experience of the surgeon and the duration of hospital stay were similar for both groups. The successful cerclage group used salbutamol for average duration of 2.2 weeks compared with the 1.94 weeks for the failed group and this difference was significant (P < 0.05). Elective and urgent cerclage procedures were more amongst successful cerclage group compared to more emergency procedures in the failed group; 84 versus 27, 8 versus 0 and 0 versus 4 respectively, P < 0.05. For those who had emergency cerclage the mean duration for which pregnancy was prolonged was 2.6 ± 2.4 weeks (a range 1 day to 6 weeks). Furthermore out of the 111 patients with previous pregnancy loss through miscarriages 68 (61.3%) had term deliveries and 23 (20.7%) preterm births with an overall fetal salvage of 98 (79.7%); as shown in [Table 5].

In this review, the recorded incidence of cervical incompetence of 0.78% is consistent with findings in the literature. [1],[13],[14] Historical background of a previous miscarriage remains key to diagnosis of cervical incompetence as was observed in this study where majority were nulliparous (28.5%) with a history of previous spontaneous miscarriages in over 90% of the study population and about 50% of them having two or more miscarriages. Furthermore a significant proportion (48%) had a history of previous use of cervical cerclage. History has been reported as the main stay of diagnosis. [1],[2],[15] In this situation use of prophylactic cerclage becomes important to improve pregnancy outcome. Consistent with previous literature we had more of prophylactic cerclage procedures (90.2%) compared with urgent and emergency. Furthermore an overall success rate in terms of prolongation of pregnancy to term of 74.8% shown in this study further buttresses the argument in favor of cerclage procedure as a measure to reducing pregnancy losses and improving fetal salvage. In this study, pregnancy outcome was quite favorable, with an overall fetal salvage of 98 (79.7%). Previous studies have reported a wide range of pregnancy outcomes from 43.8% term deliveries in Tanzania, 76.8% in Zambia to 90% of live births in Saudi Arabia; [10],[16],[17] this is consistent with our observation and in contrast to the suggestion by Steel et al. in London that poor outcome after cervical cerclage were more common amongst blacks. [11] Favorable fetal salvage rates have also been reported in African populations, with Wright [9] reporting a 94.4% fetal salvage rate, while Feyi-Waboso and Umezurike [14] reported 92.2%.

In this study, pre-eclampsia and antepartum fetal compromise accounted for the majority of the preterm deliveries. Similarly, Shamshad et al. found severe pre-ecclampsia and placenta abruption as the main causes of premature delivery. [18] In contrast a high rate of preterm deliveries was recorded in a recent Pakistan study, [19] with 65.85% of the patients falling in this group. A study done by Drakeley et al. [20] in a meta-analysis of studies on cervical stitch (cerclage) for preventing pregnancy loss in women found a significant reduction in pregnancy loss and pre-term delivery rates, however, he noted that it was not possible to rule out other causes of abortions, premature deliveries and intrauterine fetal deaths in most studies. Drakeley et al. [20] concluded that the effectiveness of prophylactic cerclage in preventing pre-term deliveries is not proven. On the other hand, in a South African survey there was no evidence that cervical cerclage either prolonged gestation or improved survival. [21]

Despite the inconsistencies that exist in the diagnosis and management of cervical incompetence, cervical cerclage has become an established treatment for cervical incompetence. The fact that the effectiveness of elective cerclage is much better when applied prophylacticaly is evident in this study where 75.7% of the elective cerclage were successful compared to 100% failed procedure of those that had emergency cerclage. While for the emergency cerclage group we observed a mean prolongation time of about 20 days, the results were more encouraging for Lefebvre et al., who reported that: The mean duration of cerclage in situ in those patients who had cerclage after some dilatation of the cervix was 84 days. The extra time gained is thought would contribute to improved survival rate, since gestational age is one factor which strongly associates with neonatal survival. [22] Overall, in comparison of type of cerclage and pregnancy outcome we found that the emergency group had a relatively poorer outcome than the elective and urgent (empirical) groups. Previous studies have reported elective cerclage to have a better outcome. [4],[5],[22],[23],[24] In the emergency cerclage group outcome is poorer due to the prolapsed membranes, advanced cervical dilatation and infection. Cardosi and Chez.[23] suggested that, proper selection of patients and prophylactic antibiotics before cerclage might help improve the outcome. Furthermore we note that there was 100% success for women who had urgent cerclage (empirical group) i.e., with ultrasound only suspicion of incompetence; this perhaps supports the argument that such patients may not have required the cerclage. [2],[7],[18],[25]

In line with existing literature the outcome of cerlage procedure in this study was not influenced by factors such as age of patient, parity, experience of the surgeon or duration of hospital stay, although we observed an association between successful outcome and longer duration of tocolytic usage (for at least 2 weeks post procedure), the influence of confounding variables cannot be excluded. In our study, tocolytics and antibiotics were prophylactically given to all patients while bed rest was advised for average duration of 3 days post-surgery. Previous studies have hypothesized that women with a cerclage were more likely to receive tocolytic drugs and have more interventions. [20],[21]

The mode of delivery was mostly vaginal but for the few who had abdominal delivery the main indications for operative delivery were fetal distress and PIH/pre-eclampsia. In a previous study [26] one of the main indications for operative delivery in cerclage patients was a failure to progress in labor, but our findings are consistent with other reports that indicates that fetal rather than maternal indications influence the rate of caesarean deliveries in women with cerclage. [27] While some studies in comparative analysis observed no significant difference in the mode of delivery, mean birth weight and APGAR score in patients with cerclage or cervical pessaries, others demonstrated an increase in operative deliveries in women with cerclage: However, this increase was not directly linked to the cerclage itself as most of the compelling indications are fetal. [26]],[[28]],[[29] In a comprehensive review of cervical cerclage, Drakeley et al. [20] noted an increase (though not statistically significant) in cesarean deliveries in the cervical suture group; one of his postulations is that pregnancies are "medicalised" once a stitch is inserted hence increased anxiety to expedite delivery, therefore, many women may be treated unnecessarily due to poor prediction and indications. This postulation is somewhat highlighted in our study with about 5% of the CS indication being a history of infertility or bad obstetric history with no living children.

Although cerclage is deemed a relatively simple and safe surgical procedure, it is not without side effects. In our study, two patients with advanced cervical dilatation who had emergency cerclage had PROM within 72 h of the procedure. In general, 13.8% of patients in this series had failed cerclage due to prom. None had cervical laceration or premature contractions as a result of the procedure and we had no documented record of vulvovaginitis or urinary tract infection. Golan etal. [30] reported frequency of PROM of 30%, whereas 15.5% of patients developed premature contractions, also one (2.43%) of the patient in the study developed cervical laceration due to contraction, McDonalds stitch was removed and cervical laceration needed stitching due to bleeding. [30] Previous studies in Nigeria reported that urinary tract infections, vulvovaginitis and PROM were the commonest complications. [14],[31] In concordance with our records no cases of urinary tract infections were seen in a 7 year retrospective study among Saudis. [17] The use of prophylactic antibiotics post-operatively as we routinely do may have influenced this findings. In addition, suture re-insertion, maternal death due to endotoxic shock has been reported. [10],[32] We did not encounter a case of maternal mortality in our study.

Conclusion

Cerclage insertion for suspected cases of cervical incompetence is associated with a potential for considerable prolongation of pregnancy and good fetal outcome; we can posit that cervical cerclage may have an important beneficial effect in carefully selected cases of cervical incompetence even amongst pregnant black African women.

Romero R, Espinoza J, Erez O, Hassan S. The role of cervical cerclage in obstetric practice: Can the patient who could benefit from this procedure be identified? Am J Obstet Gynecol 2006;194:1-9. [PUBMED]